At present, the Common Public Radio Interface (abbreviated as CPRI) standard protocol is widely used in developing a distributed base station system in the communication industry. The CPRI protocol has stipulated a standard for the interface between a radio equipment controller (abbreviated as REC) and radio equipment (abbreviated as RE) in radio base station equipment.
FIG. 1 is a schematic diagram of the linkage between an REC and an RE according to the related art. As shown in FIG. 1, one REC may link with a plurality of REs, and each RE may also link with other REs, wherein the links among the REs may be of either a chain structure or a tree structure or a ring structure.
Take CPRI for example, the CPRI stipulates that the period of each basic frame is 1/3.84 M, which is composed of one 1 control word and an IQ area containing 15 words, wherein this control word is transmitted first. 256 basic frames compose one superframe, and 150 superframes compose one 10 ms radio frame. One superframe has only 256 control word fields, some of which are occupied by protocols and therefore available control word fields are actually less than 256.
With the constant development of the communication industry, both service types and the service data amount that are supported are continuously increasing, and the requirements on the control word of the protocols are also gradually increasing. However, the total number of control words in the protocol does not develop at the same pace, which therefore brings about the following problems: with the constant development of a user system, the requirements on control words constantly increase, and the specific information required by users is also constantly increasing, thus the limited number of control words in the protocol will inevitably be unable to satisfy the development of the user system.
As regards the problem in the related art that the control words are limited in number and are unable to satisfy the requirement, currently no effective solution is proposed yet.